Stuffing of leather



V Patented Apr. 14,1931

' UNITED. STATES: PAT-Eur orrlc ALFRED THAUSS, OI COLOGNE-DEU'IZ, AND ADOLF DAHL, OF WIESDOBF-ON-THE-BHINE,

GERMANY, ASSIGNOBS TO GENEBAL'ANILINE WORKS, 1170., OF NEW YORK, N. Y

A CORPORATION OF DELAWARE STUFIING OF LEATHER Ho Drawing. Application filed December 28, 1927, Serial No. 242,285, and in Germany December 88, 1888. l

The present invention concerns 'the stufimg of leather and the products obtainable thereby, and consists in theemployment of the fatty acids derived from wool fat either before or after the dyeing of the leather; the said fatty acids arev incorporated into the leather either as such or in the form of their aqueous solutions in the stuffing drum or by rubbing in on the table before or after the dyeing. a

In order to stufi chrome-tanned and vegetable leather, as well as leather tanned in any other way fat liquors are employed, which are either incorporated into the leather by stuffing or else rubbed in. Such fat liquors consist of an aqueous emulsion of vegetable, animal or mineral fats and oils, products either soluble or insoluble in water being employed in order to obtain the desired result. The emulsification' of the materials for stufi- 'ing the leather is efiected with the aid of soap or weak alkalies.

The emulsions of fat liquors above indicated, which are in general use, involve various disadvantages in their application, which may be shortly described The liquors aresensitive to acids, that is to say, in the presence of inorganic or organic acids they lose their uniformity, separatlng fat or oily particles, which are dispersed unevenly over the leather and consequently cause the formation of spots in the currying of the leather. These phenomena become especially noticeable and unpleasant in the case of chrome-tanned upper leathers, semichrome leathers and chrome splits. 3

A further disadvantage of the fat liquors consists in that in those cases, in which for certain technical reasons leather is stuffed previous to dyeing, an uneven absorption of the dyestuffs has to be contemplated. This is especially disturbing, when the grain of ous degreasing process.

the leather to be stufied has only taken up the liquor to an incomplete extent, which in the manufacture of patent leather entails a tedidyeing and then subjecting the same to a basic topping in a fresh bath, the fat liquor which exerts a faintly alkaline reaction causes the basic dyestufi to strip.

In accordance with the present invention all the difficulties described above can be avoided by replacing the fat 1i uor hitherto used'bysulfonated atty acids erived from wool fat, such as are obtainable'by sulfonating, in the presence of a phenol, the mixture of fatty acids occurring in wool-fat, for example, by means of sulfuric acid mono- I hydrate or chloro-sulfonic acid at normal or slightly elevated temperatures.

The advantages resulting from the application of these sulfonated fatty'acids derived fromwool fat consist in that they. dissolve in water, no matter whether the water contains acid or alkaline constituents or whether it has ,a neutral reaction. In particular the non-sensitiveness to acid renders it possible to combine the hitherto tedious dyeing and stufiing operations into one single operation, which is equivalent to a less e ensive manufacture of leather and a more e cient utilization of the plant.

A further advantage accompanymg the application of the sulfonated fatty acids derived from wool fat consists in the fact that l they are quickly and evenly absorbed and fixed in the leather. The troublesome exudation of fat from the leather (an ever recurring phenomenon) can thus be avoided with certamty.

The stufiing efi'ect is of an outstanding order and exhibits in contradistinction with the stuflihg hitherto customary the great advantage that the feel of the leather remains dry and smooth without in any way prejudicing the softness and suppleness of the leather.

in The following examples will illustrate our invention: J

Example1.--In order to stuff normal, previously dyed, chrome-tanned, upper leather, 4 kg. of a fatty acid derived from the wool fat, obtainable as above indicated are dissolved in 50 liters of water at a temperature from about 40 to 50 C. and this solution is introduced into the rotating stufling drum 2 Y 1mm through the hollow axle. After about 15 the fatty acid an loyed is comgletely absorbed and fixed. y the leather.

he quantities referred to are used mconi I 5 i'unctlon with 100 by weight'of shaved eather. After the'a rption of the fat the leather'is dried and curried in the customary manner.

- Ewample 2.'"-A"solution of 4 kg. of the sulfonatedfat .acid "derived from wool fat, described a ve, in 50 kg. of water at a tem rature from aboi1t40 to 50 C. is added to e stufling drumin which 100 kg. by weight of shaved, chrome-tanned leather and "u 150 liters'of water at a temperature from f I about 40 to 50 C. have previo l been placed. The vstufling is complete after about minutes, after which the leather can be dyed in the same bath. .When the dyeing so is completed the leatherisdried and curried f in the normal manner. .9 v

Ewam Ze 8.A solution of thesulfonated' fatty acids derived fromwool fat described above in 50 liters of water at a temperature u from about to C..is rubbed on the table into the leather which is to be stuffed, either on the (grain side or on the flesh side. [We aim:

1. The recess which comprises stu fing to leather wit a product obtained by sulfonating the mixture of fatty acids occurring in wool-fat in the presence of a phenol.

- 2. The rocessv whichcom rises st leather wi an aqueous solution of a pr 88 not obtained by sulfonating the- 'mixture of fatty acids occurring in wool-fat in the pres-, ence of aphenol.

3. The process which comprises. stuflin dyed leather with a product obtained by s a fonating the mixture of fatty acids occurring r in woolefat in the presence of a phenol.

4. The process which comprises stufiing .dyed leather with an ueous solution of a product obtained by sul onating the mixture of fatty acids occurring in-wool-fat in the a presence of a phenol.

- v 5. Asanew-productofmanufactnre,leath-' or having been stufled with a product ob tained by sulfonating the'mixture of fatty to acids occurring inwool-fat. in the presenceof a phenol. v a

' 6. As'a new product of, manufacture dyed a leather having been stuffed after the dyeing with a product-obtained'by sulfona-tin the -36 mixture of fatty acids occurring in wojo -:Eat

' Pi t e a ADOLFDAHL f in.thepresence of a phenol. Y In testimony whereof, we have hereunto set [ALFRED THAUss. 

